Reflections on the structural dynamics of floating beams and ship hulls in waves

Abstract

The paper aims to shed light on links between the classical modal superposition analysis of ship hydroelasticity and the alternative formulation, more recently developed, in which equations for structural deflection and hydrodynamic pressure are coupled explicitly. The analysis is focused on a simple two-dimensional model of a uniform beam in small-amplitude waves. A new numerical representation is presented (based on a series of Legendre functions). Matrix equations are developed which provide links between the two formulations, and illustrative results are discussed. The influence of the beam flexibility on deflections and bending moments is shown, and the contributions of added mass and added damping effects are considered. The elastic wavelength in the floating beam is shown to be an important parameter.

Keywords

structural dynamics floating beams ship hulls waves

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References

Bishop

R E D

‘On the strength of large ships in heavy seas.’

S. Afr. Mech. Engr 21 (1971): 338–353

Bishop

R E D

Eatock Taylor

Jackson

K L

‘On the structural dynamics of ship hulls in waves.’

Trans. R. Instn Nav. Archit. 115 (1973): 257–274

Bishop

R E D

Price

W G

‘On modal analysis of ship strength.’

Proc. R. Soc. A 431 (1974): 121–134

Bishop

R E D

Price

W G

Hydroelasticity of ships Cambridge

Cambridge University Press

1979)

Ertekin

Riggs

H R

Che

X L

S X

‘Efficient methods of hydroelastic analysis of very large floating structures.’

J. Ship. Res. 37 (1993): 58–76

Squire

V A

Dugan

J P

Wadhams

Rottier

P J

Liu

A K

‘Of ocean waves and sea ice.’

A. Rev. Fluid Mech. 27 (1995): 115–168

Kashiwagi

‘Research on hydroelastic responses of VLFS: Recent progress and future work.’

Int. J. Offshore Polar Engng 2 (2000): 81–90

Watanabe

Utsunomiya

Wang

C M

‘Hydroelastic analysis of pontoon-type VLFS: A literature survey.’

Engng Structs 26 (2004): 245–256

Chen

X J

Y S

Cui

W C

Jensen

J J

‘Review of hydroelastic theories for global response of marine structures.’

Ocean Engng 33 (2006): 439–457

10.

Squire

V A

‘Synergies between VLFS hydroelasticity and sea-ice research.’ In Proceedings of the 18th International Offshore and Polar Engineering Conference, Vancouver, Canada, 6-11 July 2008, pp. 1–13 (International Society of Offshore and Polar Engineers, Mountain View, California).

11.

‘Report of Specialist Task Committee VI.2, Very large floating structures.’ In Proceedings of the 16th International Ship and Offshore Structures Congress (ISCC 2006), Southampton, UK, 20-25 August 2006, Vol. 2, pp. 379–430 (Elsevier, Oxford).

12.

Eatock Taylor

‘Hydroelasticity of plates and some approximations.’

J. Engng Math. 58 (2007): 267–278

13.

Cooke

Hydroelastic effects in uniform and non-uniform flat plate floating islands MEng Project Report, University of Oxford, Oxford, UK, 2004.

14.

Khabakhpasheva

T I

Korobkin

A A

‘Hydroelastic behaviour of compound floating plate in waves.’

J. Engng Math. 44 (2002): 21–40

15.

Ryansah

Wang

C M

Choo

Y S

‘Reducing hydroelastic response of interconnected floating beams using a semi-rigid connection.’ In Proceedings of the 28th International Conference on

Ocean, offshore, and arctic engineering, Honolulu, Hawaii, USA, 31 May-5 June 2009, paper no. OMAE2009-79692 (ASME, New York).

16.

17.

Stoker

J J

Water waves New York

Interscience

1957)

18.

Newman

J N

‘Wave effects on deformable bodies.’

Appl. Ocean Res. 16 (1994): 47–59

19.

Watanabe

Utsunomiya

‘An eigenfunction expansion matching method for analysing the wave-induced responses of an elastic floating plate.’

Appl. Ocean Res. 17 (1995): 301–310

20.

Bishop

R E D

Eatock Taylor

‘On wave-induced stress in a ship executing symmetric motions.’

Phil. Trans. R. Soc. Lond. 272 (1973): 1–32